Online structural state assessment for aerospace composite structures using an acousto-ultrasonics-based multi-damage index identification approach

2020 ◽  
Vol 19 (6) ◽  
pp. 1790-1807 ◽  
Author(s):  
Liang Si ◽  
Zongfeng Li
Keyword(s):  
Composite Structures ◽  
Structural Damage ◽  
Assessment Tool ◽  
Damage Index ◽  
Health State ◽  
Structural Health ◽  
Damage Indices ◽  
Damage Quantification ◽  
Identification Approach ◽  
Prediction Functions

The development of aerospace manufacturing has promoted the application of lightweight composite materials into aerospace structures. Although the aerospace composite structures possess numerous advantages, invisible internal structural damage such as delaminations induced by various external factors can significantly reduce the mechanical affordability, safety, and life-cycle of the structure. Therefore, it is of great significance to monitor and assess the health state and predict accurately the lifetime of aerospace composite structures. An acousto-ultrasonics-based multi-damage index identification approach is thus proposed in this study to identify and quantify possible multiple damage in thin-walled aerospace composite structures. In this approach, two indices for damage quantification were proposed: the energy and phase divergence indices. The energy index defines the reflected energy resulting from damage, and the phase divergence index defines the instantaneous phase variation of propagating waves due to damage. The two damage indices are obtained through the developed mode decomposition and spectral element analysis using sensor response signals collected by a transducer array placed onto the examined structure. Through a series of relevant experimental tests on the fabricated laminated composite panels with/without damage, the proposed acousto-ultrasonics-based multi-damage index identification approach was validated. The developed damage indices are competent to evaluate a structural health state in terms of damage quantification, and all of the validation results fell well in the prospected ranges. Moreover, it shows a linear and consistent trend between the variation of two damage indices and damage extents. Based on the particular relation, the linear regressive prediction functions were established separately regarding the two damage indices. They can be used to assess a structural health state due to the damage growth in real time. The proposed multi-damage index identification approach demonstrates its potential to serve as an online assessment tool to be aware of the reliability condition of a composite structure.

scholarly journals Damage Indexing Method for Shear Critical Tubular Reinforced Concrete Structures based on Crack Image Analysis

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4304 ◽  
Author(s):  
Yang ◽  
Chang ◽  
Wu
Keyword(s):  
Image Analysis ◽  
Reinforced Concrete ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Damage ◽  
Measurement Method ◽  
Damage Index ◽  
Structural Health ◽  
Damage Indices ◽  
Indexing Method

Image analysis techniques have been applied to measure the displacements, strain field, and crack distribution of structures in the laboratory environment, and present strong potential for use in structural health monitoring applications. Compared with accelerometers, image analysis is good at monitoring area-based responses, such as crack patterns at critical regions of reinforced concrete (RC) structures. While the quantitative relationship between cracks and structural damage depends on many factors, cracks need to be detected and quantified in an automatic manner for further investigation into structural health monitoring. This work proposes a damage-indexing method by integrating an image-based crack measurement method and a crack quantification method. The image-based crack measurement method identifies cracks locations, opening widths, and orientations. Fractal dimension analysis gives the flexural cracks and shear cracks an overall damage index ranging between 0 and 1. According to the orientations of the cracks analyzed by image analysis, the cracks can be classified as either shear or flexural, and the overall damage index can be separated into shear and flexural damage indices. These damage indices not only quantify the damage of an RC structure, but also the contents of shear and flexural failures. While the engineering significance of the damage indices is structure dependent, when the damage indexing method is used for structural health monitoring, the damage indices safety thresholds can further be defined based on the structure type under consideration. Finally, this paper demonstrates this method by using the results of two experiments on RC tubular containment vessel structures.

FEM Free Damage Detection of Beam Structures Using the Deflections Estimated by Modal Flexibility Matrix

2021 ◽  
pp. 2150128
Author(s):  
Wen-Yu He ◽  
Wei-Xin Ren ◽  
Lei Cao ◽  
Quan Wang
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Damage Index ◽  
Element Model ◽  
Mode Shapes ◽  
Beam Structures ◽  
Flexibility Matrix ◽  
Damage Quantification ◽  
Modal Flexibility ◽  
The Cost

The deflection of the beam estimated from modal flexibility matrix (MFM) indirectly is used in structural damage detection due to the fact that deflection is less sensitive to experimental noise than the element in MFM. However, the requirement for mass-normalized mode shapes (MMSs) with a high spatial resolution and the difficulty in damage quantification restricts the practicability of MFM-based deflection damage detection. A damage detection method using the deflections estimated from MFM is proposed for beam structures. The MMSs of beams are identified by using a parked vehicle. The MFM is then formulated to estimate the positive-bending-inspection-load (PBIL) caused deflection. The change of deflection curvature (CDC) is defined as a damage index to localize damage. The relationship between the damage severity and the deflection curvatures is further investigated and a damage quantification approach is proposed accordingly. Numerical and experimental examples indicated that the presented approach can detect damages with adequate accuracy at the cost of limited number of sensors. No finite element model (FEM) is required during the whole detection process.

Scaled Acoustics Experiments and Vibration Prediction Based Structural Health Monitoring

2008 ◽  
Author(s):  
Nesrin Sarigul-Klijn ◽  
Israel Lopez ◽  
Seung-Il Baek
Keyword(s):  
Health Monitoring ◽  
Dimensional Reduction ◽  
Structural Damage ◽  
Numerical Study ◽  
Damage Index ◽  
Time Frequency ◽  
Structural Health ◽  
Reduction Techniques ◽  
Vibration Prediction ◽  
Dimensional Reduction Techniques

Vibration and acoustic-based health monitoring techniques are presented to monitor structural health under dynamic environment. In order to extract damage sensitive features, linear and nonlinear dimensional reduction techniques are applied and compared. First, a vibration numerical study based on the damage index method is used to provide both location and severity of impact damage. Next, controlled scaled experimental measurements are taken to investigate the aeroacoustic properties of sub-scale wings under known damage conditions. The aeroacoustic nature of the flow field in and around generic aircraft wing damage is determined to characterize the physical mechanism of noise generated by the damage and its applicability to battle damage detection. Simulated battle damage is investigated using a baseline, and two damage models introduced; namely, (1) an undamaged wing as baseline, (2) chordwise-spanwise-partial-penetration (SCPP), and (3) spanwise-chordwise-full-penetration (SCFP). Dimensional reduction techniques are employed to extract time-frequency domain features, which can be used to detect the presence of structural damage. Results are given to illustrate effectiveness of this approach.

Comparative Seismic Risk Analysis of Existing Low-Rise RC Buildings Retrofitted by Metallic Energy Dissipating Devices

2013 ◽  
Vol 470 ◽  
pp. 1085-1088
Author(s):  
Dong Hyeon Shin ◽  
Jin Young Park ◽  
Hyung Joon Kim
Keyword(s):  
Probability Distribution ◽  
Risk Analysis ◽  
Seismic Risk ◽  
Structural Damage ◽  
Damage Index ◽  
Rc Buildings ◽  
Probabilistic Characteristic ◽  
Seismic Risk Analysis ◽  
Damage Indices ◽  
Rc Building

Existing non-seismically detailed low-rise RC buildings have higher seismic risks that are dependent on their seismic capacities and demand of building sites. Seismic risk analysis can be performed considering probabilistic characteristic of the structural damage. Structural damage is more accurately quantified by the damage indices than by a single engineering parameter. This study carries out comparative seismic risk analysis of a prototype building with and without metallic energy dissipating devices. Based on the probability distribution of damage index, it is demonstrated that the application of well-designed MEDDs to low-rise RC building can reduce its potential seismic risk.

Identification of multi-defects in an arched composite structure by the corrected probabilistic diagnostic imaging with the fused damage index

2021 ◽  
pp. 1045389X2110322
Author(s):  
Hashen Jin ◽  
Jun Li ◽  
Weibin Li ◽  
Xinlin Qing
Keyword(s):  
Diagnostic Imaging ◽  
Composite Structure ◽  
Shape Factor ◽  
Composite Structures ◽  
Damage Index ◽  
Guided Wave ◽  
Identification Accuracy ◽  
Size Information ◽  
Damage Indices ◽  
Ultrasonic Guided Wave

Due to the complicacy of geometry and structure in the arched composite structure, it is difficult to monitor various kinds of defects accurately. The developed damage probabilistic diagnostic imaging approach based on ultrasonic guided wave energy signal characteristics is very feasible for the structural health monitoring in the arched composite structures. However, the conventional probabilistic diagnostic imaging (PDI) approaches united with the signal energy damage indices ( DIs) have some limitations in the identification of the number, location and specific size information of multi-defects. Thus, the damage shape factor from the single damage-impaired path imminently demands to be majorized to raise the precision and stability of PDI approach in the damage recognition. A corrected probabilistic diagnostic imaging (CPDI) approach integrated with the damage shape factor [Formula: see text] needs to be recommended to precisely inspect the expansion of defect zones and different multi-defects in the arched composite structure. The availability and feasibility of the proposed methods has been validated by the experiments in the tested specimen. The results show that the fused frequency-domain energy DIs can be applied to indicate the expansion of defect zones quantitatively. It is proved that the defect identification accuracy of multi-defects from the CPDI approach can be improved by the majorization of damage shape factor, effectively. It is also clearly observed that the number, location and specific size information of different conditions of multi-defects can be distinguished by using the CPDI algorithm, availably.

scholarly journals Local Damage Indices of Frames Consisting of Composite Beams and RC Columns

2016 ◽  
Vol 10 (1) ◽  
pp. 280-292
Author(s):  
Wei Li ◽  
Linzhu Sun ◽  
Kejia Yang ◽  
Lei Wang ◽  
Dongyan Wu ◽  
...  
Keyword(s):  
Composite Structures ◽  
Damage Model ◽  
Damage Index ◽  
High Strength ◽  
Steel Beams ◽  
Local Damage ◽  
Composite Frame ◽  
Damage Indices ◽  
Study Results ◽  
Scope Of Application

The study is to propose the local damage indices of composite frame structures consisting of high-strength concrete columns confined by continuous compound spiral ties and steel beams (CCSTRCS), the local damage indices would lay a foundation for the study of the overall damage indices for composite CCSTRCS frame. The Mehanny damage model has been modified to predict the local damage behavior of composite CCSTRCS frames, it enlarges the scope of application for the composite structures compared with the previous work. The proposed model is validated by comparing with the present references. The study results suggest the different components corresponding to the extent of the damage and its damage index.

scholarly journals Impedance-based damage detection under noise and vibration effects

2017 ◽  
Vol 17 (3) ◽  
pp. 654-667 ◽  
Author(s):  
Leandro M Campeiro ◽  
Ricardo ZM da Silveira ◽  
Fabricio G Baptista
Keyword(s):  
Structural Health Monitoring ◽  
Damage Detection ◽  
Health Monitoring ◽  
Structural Damage ◽  
Low Cost ◽  
Coherence Function ◽  
Mechanical Impedance ◽  
Noise And Vibration ◽  
Structural Health ◽  
Damage Indices

The electro-mechanical impedance technique has been extensively studied in recent decades as a non-destructive method for detecting structural damage in structural health monitoring applications using low-cost piezoelectric transducers. Although many studies have reported the effectiveness of this detection method, numerous practical problems, such as the effects of noise and vibration, need to be addressed to enable this method’s effective use in real applications. Therefore, this article presents an experimental analysis of noise and vibration effects on structural damage detection in impedance-based structural health monitoring systems. The experiments were performed on an aluminum bar using two piezoelectric diaphragms, where one diaphragm was used to measure the electrical impedance signatures and the other diaphragm was used as an actuator to generate noise and controlled vibration. The effects of noise and vibration on impedance signatures were evaluated by computing the coherence function and basic damage indices. The results indicate that vibration and noise significantly affect the threshold of the lowest detectable damage, which can be compensated by increasing the excitation signal of the piezoelectric transducer.

A New Damage Index for Isolated Structures

2019 ◽  
Vol 19 (06) ◽  
pp. 1950055
Author(s):  
Niloofar Elyasi ◽  
Faramarz Khoshnoudian ◽  
Yasaman Khoshnoudian
Keyword(s):  
Damage Index ◽  
Principal Component ◽  
Lookup Table ◽  
Health State ◽  
Structural Dynamic ◽  
Damage Scenarios ◽  
Concrete Frame ◽  
Damage Indices ◽  
Uncertainty Of Measurements ◽  
Isolated Structures

Damage indices based on structural dynamic characteristics are often used to detect damage in the structures. In this study, a new index for identifying damages in base-isolated structures is proposed using the frequency response function (FRF). Since calculation of the FRF data is time- and memory-consuming for problems of large size, the two-dimensional principal component analysis technique is employed to decrease the data size. The damage indices calculated, representing the health state of the structure, are stored in a database, which are then used to detect the damage location and severity by utilizing the lookup table method. The proposed damage detection method is applied to four concrete frame models, one of which is fixed at the base and the others are isolated by elastomeric bearings. The FRF data are polluted with three different noise values (5%, 10% and 15%) in order to evaluate the uncertainty of measurements. The accuracy of the proposed indices is compared with each other for various parameters such as noise values, bearings characteristics, base conditions and different damage scenarios. The results show the precision of the proposed method.

scholarly journals A Probabilistic Damage Identification Approach for Structures under Unknown Excitation and with Measurement Uncertainties

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ying Lei ◽  
Ying Su ◽  
Wenai Shen
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Structural Parameters ◽  
Probabilistic Approach ◽  
Damage Index ◽  
Deterministic Algorithm ◽  
Measurement Noise ◽  
Identification Accuracy ◽  
Identification Approach ◽  
High Level

Recently, an innovative algorithm has been proposed by the authors for the identification of structural damage under unknown external excitations. However, identification accuracy of this proposed deterministic algorithm decreases under high level of measurement noise. A probabilistic approach is therefore proposed in this paper for damage identification considering measurement noise uncertainties. Based on the former deterministic algorithm, the statistical values of the identified structural parameters are estimated using the statistical theory and a damage index is defined. The probability of identified structural damage is further derived based on the reliability theory. The unknown external excitations to the structure are also identified by statistical evaluation. A numerical example of the identification of structural damage of a multistory shear-type building and its unknown excitation shows that the proposed probabilistic approach can accurately identify structural damage and the unknown excitations using only partial measurements of structural acceleration responses contaminated by intensive measurement noises.

scholarly journals Structural Health Monitoring Using Ultrasonic Guided-Waves and the Degree of Health Index

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 993
Author(s):  
Sergio Cantero-Chinchilla ◽  
Gerardo Aranguren ◽  
José Manuel Royo ◽  
Manuel Chiachío ◽  
Josu Etxaniz ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Pattern Matching ◽  
Health Monitoring ◽  
Structural Damage ◽  
Guided Waves ◽  
Damage Index ◽  
Guided Wave ◽  
Structural Health ◽  
Wave Measurements ◽  
Beamforming Technique

This paper proposes a new damage index named degree of health (DoH) to efficiently tackle structural damage monitoring in real-time. As a key contribution, the proposed index relies on a pattern matching methodology that measures the time-of-flight mismatch of sequential ultrasonic guided-wave measurements using fuzzy logic fundamentals. The ultrasonic signals are generated using the transmission beamforming technique with a phased-array of piezoelectric transducers. The acquisition is carried out by two phased-arrays to compare the influence of pulse-echo and pitch-catch modes in the damage assessment. The proposed monitoring approach is illustrated in a fatigue test of an aluminum sheet with an initial notch. As an additional novelty, the proposed pattern matching methodology uses the data stemming from the transmission beamforming technique for structural health monitoring. The results demonstrate the efficiency and robustness of the proposed framework in providing a qualitative and quantitative assessment for fatigue crack damage.

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